The present invention relates generally to agricultural spraying implements and more specifically to an improved apparatus for dispensing concentrates at a rate proportionate to the implement's land travel speed into a diluent which is dispersed at a predetermined constant rate.
Spray nozzles operated by water pressure provide the most satisfactory performance when operating at a pressure close to that for which they were designed. For consistent spray pattern performance and uniform coverage that operating pressure should be maintained regardless of speed assumed by the spraying implement.
A uniform coverage is most easily achieved when the density or amount of chemical injected into the water and thereby deposited on the ground or plants is constant per unit of distance traveled. Because some spraying operations are carried out from machines which travel at variable speeds, the rate of chemicals deposited cannot be consistently maintained unless dispersed in proportion to the implement's forward speed.
In the past massive and bulky pumps and drives have been required for injecting chemicals into the water stream in proportion to the vehicle forward speed. This practical limitation has been essentially one involving flow control and has effectively prohibited the use of several chemicals together or separately where each chemical's density of deposit dictated that it be provided its own ground speed regulating and metering equipment.
A further problem is often encountered when the chemical concentrate injected into the water system is not uniformly deposited on the ground or plants because the water pressure is not consistantly maintained above a minimum threshold value to assure the desired spray pattern. Accordingly, provisions should be made for preventing injection of the chemical concentrate supply into the water line whenever the water line pressure drops below that threshold pressure. Not only should provision be made for the chemical supply to be stopped when the water pressure drops below the threshold value, but also the water supply itself should be stopped.
It is therefore an object of the present invention to provide a compact variable flow rate chemical metering means having the ability to pump in direct relation to the implement's ground speed. This metering means should also be equipped with means for varying its constant of proportionality to enable the operator to inject chemicals into the water line at whatever rate is required to realize the desired deposit density upon the ground or plants.
It is further an object to provide a water supply system capable of maintaining a predetermined minimum water pressure to insure that the desired nozzle spray pattern is realized.
Yet another object of the present invention is to provide a chemical concentrate supply system that will inject chemical concentrate into the water supply line only when the proper water spray pattern is realized.
A still further object of the present invention is to provide a chemical concentrate supply system separate from the water supply to avoid the problems and expenses which occur when chemicals contaminate the water line or other chemical supply lines.
Another object of the present invention is to provide a simple and inexpensive chemical concentrate injection system having a simple mechanism for drivingly powering the chemical pump in relation to the vehicle forward ground speed.